The invention concerns an electric energy converter associating in series and/or in parallel a plurality of transformers.
There already exist converters associating series or parallel transformers.
Thus, the documents U.S. Pat. Nos. 4,339,704 and 3,419,786 describe a converter including a primary winding and several secondary windings. The converter is fed by an a.c. voltage. The secondary windings are connected in parallel to two conductors, each conductor having diodes connected in series. Thus, the two conductors are interconnected between their respective diodes by a secondary winding
The converter described in the document U.S. Pat. No. 3,419,786 includes on each conductor N+1 diodes for N secondary windings. In addition, it comprises N switches connected in series with each secondary winding.
The converter described in the document U.S. Pat. No. 4,339,704 includes on each conductor N+2 diodes connected in series, two diodes being placed between the successive secondary winding connections. Nxe2x88x921 switches connect the two conductors between two diodes connected successively in series.
These two converters make it possible to vary the output voltage by a factor N by associating the secondary windings in series or in parallel.
However, they have the drawback of requiring the use of a large number of switches and do not tolerate the tolerance to breakdowns of the primary circuit
In addition, these converters cannot function with a d.c. input voltage and the range of variation of the output voltage remains limited.
The invention seeks to resolve these problems by using a converter of simple design needing a reduced number of switches yet making it possible to obtain an equal or greater output voltage variation range and by tolerating simple breakdowns.
Moreover, the converter of the invention can function with an a.c or d.c. output or input voltage.
To this effect, a first object of the invention concerns providing an electric energy converter including:
N transformers each including one primary winding and one secondary winding,
A primary circuit connected to two input terminals on which the primary windings of the transformers are connected,
A secondary circuit connected to two output terminals on which the secondary windings of the transformers are connected.
This converter is characterised in that each primary or secondary circuit of the converter includes a set of switching means connected to N primary windings and to N secondary windings, and in that it includes means for controlling the switching means of at least one of the primary or secondary circuits, the switching means being connected so that it is possible to associate the N primary or secondary windings in series and/or in parallel by using the control means.
In a first variant, the primary circuit includes a current generator which feeds the input terminals and the secondary circuit includes a voltage generator connected in parallel to the output terminals.
In a second variant, the primary circuit includes a voltage generator connected in parallel onto the input terminals and the secondary circuit includes a current generator connected to the output terminals.
In one embodiment, each primary or secondary circuit can adopt one of the following two dual configurations:
the first configuration includes two electric conductors connected in parallel between the input or output terminals, each conductor comprising at least N+1 series switching means, the two conductors being interconnected between their respective switching means by a primary or secondary winding,
the second configuration includes N+1 electric conductors connected in parallel between the input or output terminals, each conductor comprising at least two series switching means, the conductors being interconnected two by two between their respective switching means by a primary or secondary winding.
Another object of the invention concerns a method for controlling a converter according to the invention in which the primary circuit has the first configuration
This method includes stages consisting of moving a switching pattern successively along the pairs of switching means of the primary circuit and, for each pair of switching means, of subsequently inverting the state of one of the switching means of the pair or successively the state of the two switching means of the pair.
A pair of switching means then corresponds to two switching means connected before or after a given winding.